The RAM-202U-RYM1 consists of a 1.5" diameter rubber ball connected to a flat 2.5" diameter base. The base has pre-drilled holes, including the universal AMPs hole pattern. Included are (3 quantity) (#8-32 x 3/4" PH PD Mach Screws) and (3 quantity) (#8-32 SS Nylock Nuts) that will connect the RAM-202U-RYM1 to the bottom of all Raymarine Dragonfly Sonar/GPS devices.